In a wireless local area network (Wireless Local Area Network, WLAN), when a terminal is in a power save (Power Save, PS) state, the terminal can transmit uplink data to an access device temporarily, or can also inquire or request downlink data from the access device by transmitting a PS poll (PS-Poll) frame. For example, in a wireless fidelity (Wireless Fidelity, WIFI) network, a WIFI station (Station, STA) can transmit uplink data to a WIFI access point (Access Point, AP) temporarily, or can also inquire or request downlink data from the AP.
However, data transmission efficiency of the prior art is relatively low.